code: def test_basic_tree_masking(self):
      rows = [
          {
              "text": "delays in tempe",
              "seqlogical": "[in:get_info_traffic delays in [sl:location tempe ] ]",
          },
          {
              "text": "find me the quickest route home",
              "seqlogical": "[in:get_directions find me the quickest route [sl:destination [in:get_location_home home ] ] ]",
          },
      ]
  
      vocab = self.masked_tensorizer.vocab
      masked_results = self.masked_tensorizer.tensorize(
          [self.masked_tensorizer.numberize(row) for row in rows]
      )
  
      (
          all_tokens,
          _,
          _,
          all_masked_source,
          all_masked_target,
      ) = masked_results
      for tokens, masked_source, masked_target in zip(
          all_tokens, all_masked_source, all_masked_target
      ):
          assert len(masked_source) == len(masked_target)
          assert len(tokens) == len(masked_target)
          for i in range(len(masked_source)):
              # For masked tokens, dec_target is real target tokens
              if masked_source[i] == vocab.get_mask_index():
                  assert masked_target[i] == tokens[i], (
                      str(masked_target[i]) + " != " + str(tokens[i])
                  )
              # For unmasked, target is pad token
              elif masked_source[i] != vocab.get_mask_index():
                  assert masked_target[i] == vocab.get_pad_index()
  
file_path: pytext/pytext/data/test/mask_tensorizers_test.py
imports: import types
  import unittest
  from typing import List
  from pytext.data.masked_tensorizer import MaskedTokenTensorizer
  from pytext.data.masked_util import MaskEverything, RandomizedMaskingFunction, TreeMask
  from pytext.data.sources.data_source import SafeFileWrapper
  from pytext.data.sources.tsv import TSVDataSource
  from pytext.utils.test import import_tests_module
label_desc: Use image node_id 3 for calling the MaskTensorizersTest obj's underlying member method code with example usage: obj.test_basic_tree_masking() without return types